User Persona: Carlos
Task: 12-Lead Setup Process

Figure A: Still from Sears, 12-Lead ECG Process on the ZOLL X Series-ZOLL Tips and Tricks (2:31)
On a recent call, Carlos was asked to set up a 12-lead on the patient. Carlos applied the leads in the appropriate places and went to the monitor to enter the patient’s demographics and initiate the ECG.
Entering Patient Information
To enter the patient’s age and sex, Carlos must choose from a list of options on the screen.
The monitor does not have dedicated buttons for all features but uses softkeys, which means the buttons are changed programmatically and may be used for different situations depending on the screen or device feature being used.
This can be confusing in a situation where the device user must navigate left to right to move from choosing sex to age.
Arrow Keys with Multiple Functions
In this situation, Carlos must use the arrow keys to go left and right as well as up and down, while clicking the “enter” button (a button with a circle in the middle as its only description) in between.
In Figure B (below), you can see the yellow arrow pointing to the “enter” button, and the red circle outlining the left/right and up/down arrows:
Errors Resulting From Working Quickly
In this case, Carlos accidentally pressed the buttons in the wrong order and entered the patient as a male, the default setting, when in fact the patient was female.
Without thinking, Carlos went to press what is normally the “back” button on the monitor. However, with the ECG open, this actually exited the 12-lead completely and he had to start over, causing an unwanted delay.

Figure B: Still from Sears, 12-Lead ECG Process on the ZOLL X Series-ZOLL Tips and Tricks (5:10)

Figure C: Still from Sears, 12-Lead ECG Process on the ZOLL X Series-ZOLL Tips and Tricks (2:31)
What went wrong here?
For someone who uses the monitor every day, this is a skill they can acquire over time, and they become used to the limited button options.
However, for someone who does not use this very often or is in a high-stress emergency situation, this can be quite frustrating. Additionally, the soft keys are offset from the icons on the screen.
Because of the UX law of proximity, this makes it confusing for the user at first glance because it is not initially obvious which key lines up with which icon on the screen.
Furthermore, some icons have text and some do not, making the layout inconsistent and learnability more difficult.
Given this context, it is easy to understand how someone like Carlos could make mistakes when working in a hurry or with a lot of distractions.
Proposed Improvements
Main UI Screen
My next step was to recreate a Zoll monitor in Figma, implementing my proposed revisions to the interface: